I'm trying to wind a set of helicals to use mobile on HF, and I'm
wondering what guides there are. I have made them by close winding a
half wavelength of wire on the rod, and have tried close winding on the
top section of the rod, then widening the turns beteeen there and the
base feedpoint. A length of 3/4 wavelength of wire is suggested there.
But I am getting very weird effects. Can someone who has done this give
me some tips please? I have searched the net, but find very little on
this subject. I use a GDO, simple z bridge, and a vswr meter of course.
Briefly, the weird effects include the freq DROPPING as wire is pruned!
And an inability to get above 13.5 MHz if aiming at 14 MHz...it
fluctuates as wire is cut and spacing is altered.
Frustrating.
Any tips & help appreciated.
Thanks,
Adrian
VK5AW